The invention concerns a fastening tab for a diaper, or the like, particularly, a pressure-sensitive adhesive diaper fastening tape or mechanical fastener element.
Most conventional diaper fastening tabs are pressure-sensitive adhesive tapes or mechanical fastening elements that are rectangular in shape. This regular shape has the advantage in that it is easily converted (e.g., cut) from a stock roll or web into the individual fastening tabs and attached to the diaper, for example, as described in U.S. Pat. No. 3,848,594. However, this design is limited in terms of the fastening characteristics obtainable with a given pressure-sensitive adhesive or mechanical fastener hook and loop structure.
An alternative fastening tab design to the conventional rectangular shape is described in UK Patent Application No. 2 185 383 A. In this patent, the free end (the end attached by the user) of the diaper fastening tab tapers from its outermost peripheral end to its base, where the width is approximately that of the manufacturer's bond end of the fastening tab. A problem with this type of construction or design is that the distal end of the user-applied free end of the fastening tab can be removed at relatively low peel forces, making the tab more easily removable by the infant and increasing the potential for tab failure.
A fastening tape tab structure incorporating features of the rectangular tab and that of UK Patent Application No. 2 185 383 A is described in European Patent Application No. 379 850. In this patent application, the distal end of the diaper fastening tape tab free end is generally free of adhesive in a small tapered distal end portion of the free end tapers. The remaining user applied free end portion of the diaper fastening tape tab has a conventional rectangular shape. The advantage of the tapered adhesive-free distal end portion, of the fastening tape tab free end, is the reduction of sharp corners that children might accidentally cut themselves upon. The performance of the tape tab described in this patent would not be substantially different from that of conventional fastening tapes. Further, significant waste product would be created in the manufacture of these diaper tape tabs from a standard adhesive-coated stock roll or web.
An approach similar to that in European Patent Application No. 379 850 is described in UK Patent Application No. 2 206 506 A. A rounded end is similarly provided to protect against irritation from sharp corners to either the parent or the baby. This design would likewise have the limitations of European Patent Application No. 379 850.
Recently issued U.S. Pat. No. 5,312,387 describes a diaper fastening tab with a rectangular manufacturers bond end and a rounded free end. The rounded free end has a maximum width x-y at a distal half and a minimum width y at a proximal half. The fastening tab can be continuously cut from a roll of stock material with little or no tape waste. The design provides a maximum peel force resistance at the distal end of the fastening tape tab decreasing the potential for tape pop off. This design, although advantageous, is difficult for some diaper manufacturers to implement due to the required tape width and can provide some sharp corners on the manufacturers bond end.
There continues to be a need for improved diaper fastening tab designs from the prospective of user friendliness, performance, manufacturability and cost. The invention is directed at providing a novel fastening tab design which is advantageous in terms of all these perspectives. Particularly, the novel fastening tabs can be readily cut from a stock roll without creation of waste and provide fastening tabs with improved peel performance relative to conventional tab designs.